The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Feed pumps have a displacement volume, which depends on the rotational speed of the feed pump and the drive thereof. Depending on the system resistance of the power-consuming device or the devices consuming the delivered hydraulic medium, the system pressure also depends on the displacement volume. In general, there is a desire to maintain the system pressure at a constant level or at least within a defined range.
From DE 101 04 635 A1 a method is known for maintaining a constant output value of a feed pump. With this method, the rotational speed of the pump drive is controlled as a function of the output pressure of the feed pump. This requires a controllable transmission, which under certain circumstances can be very complex and costly, depending on the power output of the feed pump.